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Patented Aug. 9, 1881.

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INVENTOR ATTORNEYS.

(No Model.) I

J. B. BENNETT.

y ACOUSTIC TELEPHONE. No. 245,436.

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WITNBSSBS i UNITED STATES PATENT OFFICE..

JOHN B. BENNETT, OF SAN LUIS OBISPO, CALIFORNIA.

ACOUSTIC TELEPHONE.

SPECIFICATION forming partV of Letters Patent No. 245,436, dated August9, 1881. Application filed May 27, 1881, (No model.)

To all whom it may concern.

Be it known that LJoHN B. BENNETT, of San Luis Obispo, in the county ofSan Luis Obispo and State of California, have invented a new an dImproved Acoustic Telephone 5 and I do hereby declare that the followingis afull, clear, and exact description of the same, reference being hadto the accompanying drawings, forming part of this speciication, inwhich- Figure 1 is a vertical section through the line a; x ofFig.2looking in the direction of the arrow. Fig. 2 is a vertical sectionthrough the line y y of Fig. l, looking in the direction of the arrow.Fig. 3 is a horizontal cross-section through the line z z of Fig. l.

My invention relates to an acoustic or mechanical telephone in whichcertain improvements, the nature of which will hereinafter appear,render the instrument more eiicient in giving alouder and clearer soundthan has hitherto been obtained, and of such construction that it can beplaced in almost any place or position required.

Referring to the accompanying drawings, A represents the outside box orease. Theobject of this box or case is to intensify the sound, and alsoto give the instrument a more ornamental appearance.

I prefer to make the case with a false back or side, B, in whichappropriate openings M render it a sounding-box; butit need notnecessarily be made with this false back or side, for it is .evidentthat if the case A is properly constructed, the material selected withdue regard to its sounding qualities, it will greatly assist ininereasingthe sound,while the supplemental sounding box or board B willgreatly assist the caseAin intensifying thesound,whieh is the principalobject of the ease, as in this way I obtain the proper surroundings forthe otherwise comparatively weak power of mechanical telephones.Icanfurtherimprove the character ofthe case A as a sounding-box, andprevent resonance', Ste., that would in a measure interfere with thecomposite vibrations when speaking by making suitable apertures in thecase, preferably in the front or sides.

D represents the speaking-tube, one end of which is connected directlyto and is in open relation with the chamber Cr and vibrator L, the otheror outer end being in convenient position to speak into. This outer endmay be enlarged iiaringly, as shown, or be provided with a ilaringmouth-piece, the object in view heilig to concentratethesouiul-wavesupon the vibrater L at or near its center. This tube D is represented ascurved, and can be made from metal, hard rubber, papier-mache, wood, orother substance. It can also be a curved or straight liexible tube thatcan be curved at pleasure; or it can be made with an elbow and angled,or it can bepartflexible and part metal or other substance.

My object in using a tube that I can curve, as describethis this: Inmechanical or acoustic telephones the line or wire should extend atright angles from the diaphragm or vibrator. IVhen the speaking-tubeisstraight and placed in a convenient position to speak into or hear from(which would be a horizontal position, or at a very slight angle onlyfrom the horizontal) the line or wire must necessarily extend from ithorizontally, or with but a slight angle from the horizontal, and wouldconscquentlyin most cases be in the way, and the places in which theinstrument could be placed would be limited to the few positions wherethere would be no objection to the wire extending out from ithorizontally. By curving the speaking-tube the wire or line can extendupward from the diaphragm or vibrator to any desired height, to theceiling, or through the roof, if desirable, and then turned to whicheverdirection required. As will be seen, the line in this way can be keptentirely out of the way and the instruments placed in almost anyrequired position.

There will be a few instances where a straight tube can be used to someadvantage, and the line leading out horizontally from the diaphragm.Consequently I do not confine myself strictly to a curved or angledtube.

Vithin the case A, and connected directly or indirectly with the tube D,or forming a part of the same, is the piece or plate F, with a suitableopening, H, where it is in connection with thc speaking-tube D. Theinner or upper surface of the piece F forms one wall of theconcentrating-chamber G, the vibrator or diaphragm forming the otherwall or side. The recess or chamber G can be formed in the piece F, ormay be formed by placing a band, ring, or washer of suitable diameterand thickness IOO between the outer edge of the upper surface of thepiece F and the vibrator L, so as to keep them separated the requireddistance.

As the piece F forms the wall of the concentrating'chamber G, it shouldbe of a nonvibratory character, firm and solid, so as to re- Sist thesound-vibrations caused in the chamber G when talking into the tube D,so that the full force of the vibrations shall be expended on thevibrator L. For this purpose I use a thick piece of wood or hard rubber,but do not coniine myself either to the substance used or to thethickness of the same. Neither do I confine myself to any particularform of the piece F, as it may be circular, square, oblong, Ste.,providing the chamber Gthereon is formed perfectly round where it is inconnection with the diaphragm. Neither dolconfine myself to anyparticular method ot' holding the vibrator L in position so as to coveror form one side of the chamber G, with which the speakingtube D is inopen relation; but the method I prefer is by means of the iianged ringK, which can be provided with threads to engage with other threadsformed on the circumference of the piece F, so that it can be screwed uptightly, the flange of the ring holding the vibrator L tightly inposition; or I can form small lips or inward projections on the ring K,to engage in grooves and notches formed on the circumference of thepiece F, or can secure the piece F by small bolts, screws, or theirequivalents. The piece K need not necessarily be round, eX- cept thatportion that bears directly or indirectly against the vibrator ordiaphragm L.

I represents a hearing-tube, shaped, after the manner of thespeaking-tube, something like a curved funnel, with the larger end inopen relation with the diaphragm L from the opposite side to that of thespeaking-tube D and chamber G. This tube receives from that side of thediaphragm all the sound-waves caused by the vibrations of the diaphragmand focalizes them to the smaller end, where they are received into theflexible tube T, which is attached thereto. The tube T is provided withan appropriate ear-piece, which can be applied to the ear. The tube I isheld in position, so that its larger end is directly over and in openrelation with the diaphragm L, by the piece or ring K, to which it maybe secured; or it may be secured to the piece F, holding the diaphragm Lin position between the chamber G and the larger end of the tube I. Thetube need not always be curved, but can extend through the end of thecase A.

The advantage of having both speaking and hearing tubes is, rst, in itsconvenience, the operator being able to hear immediately upon ceasing tospeak, and to speak at once upon ceasing to hear; but the additionaladvantage in this telephone is in the improved shape of the two tubes.

In mechanical telephones where theintensity of the sound is determinedby the favorable surroundings, by which it is not decreased after beingtransmitted, it is necessary that these surroundings be adapted to thatend. With this in view it will not do to obstruct any of the wavescaused by the agitation of the vibrator or diaphragm. They must becollected and transmitted to a given point. But if the same tube is usedboth to speak and hear through, this object is not obtained, because itis found that the best form of a tube in which to speak is one whichtapers inwardly toward the vibrator or diaphragm, so that the soundwavesmay be focused directly upon its center; but when such a tube is used tohear through, the waves from the vibrator are obstructed, except at itscenter, and then those that pass through are not focused, but, on thecontrary, are scattered out and lose their force.

In my invention I have provided separate tubes with the best shapes foreach purpose. The speaking-tube D concentrates the sound upon the centerof the diaphragm, while the hearing-tube I receives the waves from thefull surface of the diaphragm and focuses them toward its smaller end,whence they are convcyed to the ear by the flexible tube T, with itsear-piece attached.

W represents the line which is connected to the vibrator or diaphragm Lat or near its center.

In using the instrument we speak into the tube D, the soundwavesstriking the vibrator L, causing it to vibrate. The line IV, beingconnected with the vibrator, transmits the vibrations to the vibratorot' the other instrument, causing it to vibrate and reproduce theoriginal sounds.

In respect to the case of the instrument I would state that I do notconfine myself to any particular shape for the same, as it can be eitheroblong, square, circular, or of any other desired form.

For calling the telephone at the other end of the line, I place aclock-alarm gear, I), :in the case and extend its hammer through a smallslot in the hearin g-tube, so as to strike against the diaphragm. Thisalarm-gear I provide with a handle, It, outside of the case, by turnAing which the hammer is made to sound an alarm on the diaphragm and callthe other telephone. Instead of putting this ham mei` inside thehearing-tube, I may place it outside and cause it to strike against thehearingtube itselt.

Having thus described my invention, what I claim is- 1. In an acousticor mechanical teleph one, the combination of the speaking-tube D,opening into the concentratingchamber G, and the hearingtube I, adaptedto fit over the diaphragm L from the opposite side to the chamber G, andgradually contracted, so as to concentrate the sound-vibrations anddeliver them to the ear-piece or ilexible tube T, substantially asdescribed.

2. In a telephone, the combination, with the diaphragm, ot' aspeaking-tube and hearing-y IOO IOS

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tube arranged upon opposite sides of the diaphragm, the said speakingtube being arranged to converge toward the center of the diaphragm andthe hearing-tube being arranged to cover the diaphragm at its end andconverge away from the said diaphragm, as and for the purpose described.

3. In atelephone, the combination, with the diaphragm, of a taperinghearing; tube arranged upon the opposite side to that which receives theimpulses ofthe voice, and with its wider end concentric in relation tothe diaphragm, substantially as shown and described.

4. The tapering and concentrating tube I, having a flexible tube, T, atits smaller and outer end and its inner and larger end curved andinclosing the diaphragm L, whereby the vibrations received by thediaphragm are con veyed away, substantially as described.

5. In combination with the diaphragm L and hearing-tube I, the heavydisk or plate F, arranged between the diaphragm and speaking tube, andhaving its top concaved to form a basin or chamber, G, and connectedwith the diaphragm and hearin g-tube bythe lian ged rin g K,substantially as and for the purpose described.

6. In combination with the diaphragm L, disk F, havingvocalizing-chamber G, and the funnel-shaped hearing-tube I, the curvedspeakin g-tube D,in open relation with the diaphragm B and the attachedline, substantially as and for the purpose described.

7. In combination with the mechanical telephone herein described,consisting of the tubes D and I, disk F, with vocalizing-chamber G,diaphragm L, and line, the outside ease orboX, A, acting as asounding-box, substantially as described.

S. In combination with the mechanical telephone herein described and thesounding-box A, the supplemental sounding-box formed by the false backB, substantially as described.

9. The speaking-tube D, with its Haring mouth-piece, in combination withthe heavy non-vibrating disk F, having vocaliZing-chamber Gr, diaphragmL, line Wr, and soundingbox A, substantially as described.

10. The combination of a curved speakingtube, D, a disk or plate, F,having a concentratingchamber, G, in open relation to the speaking-tubeand the diaphragm L, substantially as shown and described.

JOHN B. BENNETT.

Titnesses J. M. WlLcoXoN, H. LooBLrNER.

